Method of coating ferrous articles



Patented May 3, was

METHOD OF COATING FERROUS ARTICLES Michael M. Rubin, Warren, Ohio,assimor to The Thomas Steel Company, Warren, Ohio, a

corporation of Ohio No Drawing. Application May 8, 1936,

This invention relates, as indicate of applying alloy coatings toferro'u has reference moreparticularly to the production of abrass'coatingon such ferrous articles as wire and strip.

QR has heretofore been proposed coatings on ferrous articles byelectrodeposition on the articles of the alloy, or by immersing thearticles to be coated in a molten bath 'of the aly. These methods havegenerally .provenunsatisfactory, as they do not result in the productionof a coating of uniform thickness and homogeneity or one that adheres tothe base metal with sufllcient tenacity to render the article capable ofbeing subjected to bending and other fabricating operations.

It is an object of the present A further object of the invention amethod of the characterdescribed which is preferably continuous incharacte may, if desired, consist of separate, di

ous steps or operations.

To the accomplishment of tion setting forthin detailon'e an of carryingjout, the invention method, however, constituting various ways in whichthe principle tion may be used.

The method, broadly stated,.

rately electrodepositing. .on thei feifrous.afiicle, such as strip orwire, the metals" forming thegalg loy or brass coating, andsubsequentlyheattreat ing the coated article in a controlle free fromoxidizing gases.

.In providing, for example, a commercial yellow brass coating on steelstrip, 1 first deposit on the strip, by any of the approved methods ofelectroplating, a coating of copper in a about .1 oz. of copper persquare surface. I then deposit upon the ing thus formed, and in asimilar manner; a coating of zinc in an amount of about .05 oz. persquare foot' of surface. I then the article, thus provided with coatingsof copper and zinc, through a controlled atmosphere, fr ee,from oxig'dizing gases, such as oxy emcarboni' dioxide, etc; a and havingatemperature of about 700- F. to'

about 1500 F., and maintain'the. article :a't-thi's temperature fromabout 10 to about 30 minutes;

invention to provide a method whereby ferrous articles, such as wire andstrip, are coated with a bright,-uniform, closely adherent coating ofbrass.

the foregoing and related ends, said invention, then,gconsists stepshereinafter described and a pointed ioutinthe claims, the'jfo'llo in"descrip- (1, to methods s articles, but

or for a period of time sufllcient to permit a complete alloying of thecoatings to form yellow brass, the period of time of heating depending fupon the thickness of the separate coatings and the specifictemperatures employed. to formsuch The brass coating, thus formed, isbright, of uniform thickness, homogeneous in character, and adheres tothe ferrous base metal with a tenacity sufflcient to render the articlecapable of being subjected to bending and various other 10 operationsemployed in fabricating the article.

Because of the ease and accuracy with which the electrodeposition of theindividual metals, copper and zinc in this instance, may be controlled,the composition of the alloy coating may bemore closely and readilycontrolled than in the case of the method previously referred to inwhich an alloy coating is directly deposited on the base metal. Thus,coatings of any.of the well-known forms of brass may be obtained bymerely varying the thickness of the coating of each of the individualmetals, since in this manner any desired ratio of such metals ,may beobtained, and it is unnecessary to change the composition of the platingbaths. The method, as 26 thus described, is preferably carried out in ail 1 continuous manner, that is by causing the ferrous strip to travelcontinuously and uninterruptedly through the separate plating baths andthe con- -t'roll'ed heated atmosphere, but it will be under- 30 f stoodthat the method may also be carried out in a series of separate ordiscontinuous steps or operations. It will be also understood that ina 1stead of firstdepositing the copper, as described, the basemetal may beinitially coated with zinc"; e Other modes of applying the principle ofmy invention may be employed, instead of the one 'eirplained, changebeing made as' regards the methodherein' disclosed, provided the stepor40 1 steps statedby-any of the following claims or the equivalent ofsuch stated step or steps be employed.

Itherefore particularly point out and distinctlyf claim, as myinvention:

1 Themetho'd of coating ferrous strip and the likewhich comprisescontinuously moving and consecutively-subjecting the strip to the actionof a copper electro-plating' bath to form a coating of, copper directlythereon and then to the 50 action of a' zinc electro-plating bath toform a coating of zinc directly on the copper and finally to heating ata temperature of about'lOO" F. to about 1500 F.'in an non-oxidizingatmosphere,

for from about 10 to about 30 minutes, whereby 66 is to provide r, but'which scontinuwherea if amount offoot of strip copper coatj-I $410,? tocause an alloying of the'copper and zinc to form a non-peeling coetinplating bath to a of brass. on the copper 2. The method oi coatingferrous strip and pe'reture or! the like which comprises consecutivelysublectnon-oxidizing e 5 in: the strip to the action of I. copperelectroall of the plating bath to form a coating or copper directlypeeling coating thereon and then to the ection of p zinc electro-'

